From 168da39ae24b84f78525280a8d6750dd3cf1a176 Mon Sep 17 00:00:00 2001
From: Elizabeth Mattijsen <liz@wenzperl.nl>
Date: Tue, 15 Jun 2021 09:50:51 +0200
Subject: [PATCH] Simplify Iterable eqv Iterable

By removing the specific Positional handling.  This every so lightly
improves performance on comparing arrays, while not affecting any
other performance.

This also removes the use of AT-POS in eqv handling, making it easier
to later introduce proper eqv handling of sparse arrays.
---
 src/core.c/Iterable.pm6 | 66 ++++++++++++++---------------------------
 1 file changed, 23 insertions(+), 43 deletions(-)

diff --git a/src/core.c/Iterable.pm6 b/src/core.c/Iterable.pm6
index cbf12569e88..d8afcee969a 100644
--- a/src/core.c/Iterable.pm6
+++ b/src/core.c/Iterable.pm6
@@ -110,51 +110,31 @@ multi sub infix:<eqv>(Iterable:D \a, Iterable:D \b) {
         nqp::if(                                 # not same object
           nqp::eqaddr(a.WHAT,b.WHAT),
           nqp::if(                               # same type
-            nqp::istype(a, Positional),
-            nqp::if(                             # Positional
-              a.is-lazy,
-              nqp::if(                           # a lazy
-                b.is-lazy,
-                Any.throw-iterator-cannot-be-lazy('eqv','') # a && b lazy
-              ),
-              nqp::if(                           # a NOT lazy
-                b.is-lazy,
-                0,                               # b lazy
-                nqp::if(                         # a && b NOT lazy
-                  nqp::iseq_i((my int $elems = a.elems),b.elems),
-                  nqp::stmts(                    # same # elems
-                    (my int $i = -1),
-                    nqp::while(
-                      nqp::islt_i(($i = nqp::add_i($i,1)),$elems) # not exhausted
-                        && a.AT-POS($i) eqv b.AT-POS($i),         # still same
-                      nqp::null
-                    ),
-                    nqp::iseq_i($i,$elems)       # exhausted = success!
-                  )
-                )
-              )
+            nqp::iseq_i(
+              nqp::istrue(my \ial := (my \ia := a.iterator).is-lazy),
+              nqp::istrue(           (my \ib := b.iterator).is-lazy)
             ),
-            nqp::if(                             # NOT Positional
-              nqp::iseq_i(
-                (my \ia := a.iterator).is-lazy,
-                (my \ib := b.iterator).is-lazy
-              ),
-              nqp::if(
-                ia.is-lazy,
-                Any.throw-iterator-cannot-be-lazy('eqv',''),
-                nqp::stmts(
-                  nqp::until(
-                    nqp::stmts(
-                      (my \pa := ia.pull-one),
-                      (my \pb := ib.pull-one),
-                      nqp::eqaddr(pa,IterationEnd)
-                        || nqp::eqaddr(pb,IterationEnd)
-                        || nqp::not_i(pa eqv pb)
-                    ),
-                    nqp::null
+            nqp::if(
+              ial,
+              Any.throw-iterator-cannot-be-lazy('eqv',''),
+              nqp::stmts(
+                nqp::if(
+                  nqp::istype(ia,PredictiveIterator)
+                    && nqp::istype(ib,PredictiveIterator)
+                    && nqp::isne_i(ia.count-only,ib.count-only),
+                  (return False)
+                ),
+                nqp::until(
+                  nqp::stmts(
+                    (my \pa := ia.pull-one),
+                    (my \pb := ib.pull-one),
+                    nqp::eqaddr(pa,IterationEnd)
+                      || nqp::eqaddr(pb,IterationEnd)
+                      || nqp::isfalse(pa eqv pb)
                   ),
-                  nqp::eqaddr(pa,pb)     # both IterationEnd = success!
-                )
+                  nqp::null
+                ),
+                nqp::eqaddr(pa,pb)     # both IterationEnd = success!
               )
             )
           )